Many first cars do look and sound a bit boring and most couldn't really be considered 'sporty', hence the desire to improve its looks and/or handling. Many are unfortunately unsuccessful - why ?
From a tasteful spoiler to extravagant full bodykit, you can spend from a few tens of pounds to tens of thousands of pounds. Most spoilers will have little or no real improvement on reducing drag or lift - many will do the exact opposite! They also add weight, especially a full bodykit, making your car slower and less agile.
The only real positive effect these parts have is visual improvement but remember "beauty is in the eye of the beholder". You might love it but you could end up with an expensive 1.1 litre hatch that's difficult to sell when you want to move on to something really interesting....
For a few hundred pounds you'll be able to fit larger diameter wheels and lower profile tyres, these usually make any car look better but there are many trade-offs - worse ride and heavier steering are just two of them. There's also an increased risk of damage to the wheels and tyres, either from hitting a pothole or 'kerbing' them when parking. A low profile tyre needs a stiff sidewall to keep the tread in the right place and keep the wheel from touching the ground and they'll probably run at higher pressures too. These 2 differences will have the effect of passing more of the road inputs through into the body of the car, resulting in less comfort and usually more road noise too.
You can use this tyre converter to find out what different size wheels and tyres are possible - it's the 6th one down. You need to know your existing wheel and tyre sizes and an idea of the ones you want to fit.
The good thing about wheels and tyres is that you can easily take them off before you sell your first car and sell them seperately. Providing you look after the ones you take off, that is.
Lowering a car, generally by fitting shorter, stiffer springs will probably look better and not roll so much in corners but the ride will suffer and you'd better make sure the tyres are clear of the bodywork throughout their travel, especially if you're also fitter wider tyres. If they do touch, the least that might happen is that you hear a 'graunch' noise as the tyre hits a piece of trim, the suspension or the bodywork and the worst is that the tyre could be damaged or punctured when it touches something it shouldn't. What happens next depends on what you're doing at the time and how lucky you are....
Uprating the dampers is often done at the same time but make sure you're prepared for the effects - you might start to hear squeaks and rattles that weren't there before and if you go overboard you might need to visit your dentist to put your fillings back in.
If you don't know what you're doing, get some help before you start otherwise you might do yourself an injury trying to fit them. It's possible to revert back to the original parts when you come to sell your first car, it's just a bit time consuming.
A new exhaust ? An induction kit ? A turbo ? Unfortunately all these are almost certainly no-nos for your first car as there are very, very few insurance companies that will even offer to quote on one. Probably your best bet is Adrian Flux modified car insurance. But if you can wait a couple of years it becomes more of a reality.
Fitting serious ICE kit to your first car is tempting as the standard stuff will be pretty feeble but make sure you've got it covered on your insurance because if you don't and it gets nicked, it'll be you that's out of pocket.
If you do plan to make any modifications to your car you must discuss it with your insurance company as it will almost certainly affect your premium. Not telling them and just doing the mods anyway could leave you without any insurance cover when you've had an accident, for example. Then the police might take much more of an interest as you'll have been driving without insurance. That'll be points on your licence and probably more.....